The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
The present disclosure broadly relates to compositions and methods for controlling fluid flow between a wellbore and a subterranean formation.
During well construction, well production and well abandonment it may be necessary to perform operations which require minimizing or terminating fluid flow between wellbore and formation. In the majority of cases, such operations are performed to restore, prolong or enhance the production of hydrocarbons. In addition, the production tubing, artificial lift equipment or casing may be removed and replaced during a workover operation.
To maintain well control, workover operations require that the well be filled with fluid with hydrostatic pressure in excess of the reservoir pressure. It is commonly referred as well “kill” operation. Well kills may be achieved by a variety of means, including the introduction of drilling or completion fluids that exert sufficient hydrostatic pressure in the wellbore to prevent formation fluid production. The fluid is often maintained in the wellbore for the entire duration of the workover operation. In some instances fluid leaks off into formation and fluid level cannot be maintained. Differential depletion of reservoir layers or large height of the reservoir presents another challenge—workover or kill fluid may be lost into one layer while other(s) flow reservoir fluids or gas into the wellbore. It is necessary to prevent formation fluids from entering the well during the procedures.